How to apply a texture only to certain parts of mesh?
Sounds like you need an object with two or more materials.


Under the 'Materials' tab on the right of your interface, click that "+" icon next to your single material, "Material.000".
When that happens you get a second material slot to which you may assign faces of your model. Either select a pre-existing material from your drop-down menu, or create a new material to use.
Select the faces you want to assign this new material, and with the
new material highlighted, click "Assign", under the materials list.


You'll see some other useful tools under the materials list that come in handy for assignment and selection.